Rumors are about that indications in the new ending animation and song are that the series is going to end this march. We can't be certain that isn't just another joke by the staff as they have pulled in the past. With manga material running low it's possible it could be true. Other rumors are that the last episode to be aired will only be for the year until more material comes out. Whatever the case it will be sad when this series comes to a close, be it now or later.

Hmm... from what I heard from my friend, he says that Gintama was falling down the popularity list. I really haven't seen the anime, tbh.

I sure hope they don't end the anime yet. Then again, they did pull something like this off in the past as well, and in the end the anime is still running.
I don't know about the manga though. Perhaps it's coming to an end?